Archive for August, 2008

Last week I wrote an entry about the Terri Schiavo case, discussing a new published study criticizing the news reporting of this controversial case. The case involved the right to life of a woman in a persistent vegetative state (PVS) and the relative rights of her husband vs her parents to decide her care. Michael Egnor, a neurosurgeon who writes for the Evolution News & Views blog, and with whom I have had a long blog debate, mostly about dualism and the nature of consciousness, has responded to my post on Schiavo. Not surprisingly he has taken a different view of the case. He writes:

In my view, the political efforts to save Ms. Schiavo’s life were well-intentioned and completely justified. I believe that many of the medical opinions offered publicly by physicians who favored withdrawal of Ms. Schiavo’s hydration and nourishment were rank pseudoscience. What was done to Ms. Schiavo was an atrocity.

He also offers to have a blog discussion about the topic with me, writing:

A detailed and thoughtful public exchange of views about the Terri Schiavo case by two experts in neurological medicine—an academic neurologist and an academic neurosurgeon who have quite different opinions on this matter—would be very informative. The discussion could take the form of detailed exchanges between Dr. Novella and me on specific aspects of the case, such as the autopsy report, the neurological exams, the nature and reliability of the diagnosis of persistent vegetative state, and the ethical and political issues involved. This discussion extends to many of the issues involving the materialist inference in neuroscience that Dr. Novella and I have debated over the past year.

So here is my first installment. I will focus on the nature of persistent vegetative state and respond to some of the comments of Dr. Egnor.

I enjoy science fiction partly because it can be a thought experiment on the potential course of future technology. A common sci-fi theme is the merging of man and machine and the blurring of distinction between the two. Clearly this is a process that has already begun, but even the most thoughtful futurists cannot tell where this will lead with anything but the broadest brush strokes.

In the campy sci-fi flick Saturn 3 (1980), the character played by Harvey Keitel builds a robot (Hector) with a modified human brain as it’s CPU. Keitel trains the robot partly by imprinting his own brain patterns onto it. As he is a dangerous criminal psychotic, antics ensue.

The prequels to the classic Dune series, written by Frank Herbert’s son, Brian, along with Kevin J Anderson, the primary enemies of humanity are cymeks – immortal human brains that can inhabit their choice of robotic bodies – from battle armor to space ships.

In 2061: Odyssey Three, Arthur C Clarke paints a future where every human is equipped in infancy with a “brain cap.” This is a super-computer that fits nicely over the skull, sending electrodes down into the brain in order to seamlessly interface with it and greatly expand human intellectual capacity.

In Stephen R. Donaldson: The Gap Series (1990-94), a major plot element is the “zone implant.” This is a computer device implanted into the human brain in order to enhance and control its function. They are outlawed because of they offer complete control to whoever holds the remote control to someone’s implant. But they are also portrayed as useful for the treatment of psychological and neurological disorders.

And, of course, in the new Battlestar Galactica series (I highly recommend this series to any sci-fi fan, and even if you are not a sci-fi fan this is simply superb drama) the Cylons have created humanoid robots that are indistinguishable from normal humans but have Cylon AI.

This is just a sampling running the spectrum from brains controlling robots to AI controlling human bodies with brain-AI interfaces in between. At present we are just taking the first baby steps toward whatever version of these fictional futures await us, if any. Time will tell.

Confidence in our beliefs is just another neurological function. We all have knowledge and we mentally assign a level of confidence in each piece of knowledge we think we have. Sometimes the assignation of confidence level is conscious – we may be asked how sure we are about something. And sometimes it is not conscious but it affects our behavior.

Often different individuals may even confront each other on their relative levels of confidence, when they each believe contradictory information. This conflict is sometimes encapsulated in the phrase, “You wanna bet?”

For the critical thinker it is important to avoid unjustified confidence, and to understand what factors may lead us to a high degree of confidence when we are in fact wrong. For example, we often assign a high degree of confidence to memories that are vivid and accessible, but the evidence shows that these factors do not predict accuracy. A memory may feel completely real, but be completely wrong.

The ever-present video camera is creating a new form a “paranormal” news. Anytime anything even slightly strange occurs on a video surveillance camera someone is likely to cry “ghost.” The local news media will eat it up. They will interview a bunch of people and then choose the most sensational nonsense to air. The video will find its way onto the internet, and it will zip around the ether for a few days, finally fading from the public’s short attention span.

Last year we were told there was a blue ghost haunting a gas station. The video shows a fuzzy blue blob bouncing around the image. For some people, the fact that the image was the slightest bit unusual and could not be instantly explained was enough to trigger the argument from ignorance – I don’t immediately know what that is, therefore it is something paranormal, perhaps a ghost or angel. For those with more of an inclination for critical thinking, it was a small mystery to be solved – but the assumption was that it was something physical and therefore knowable.

It turns out that the blue blob was an insect crawling on the lens of the camera. Close examination of the movement of the blob convincingly shows it to be very insect-like. The movement never went behind anything in the field of view, so it was closer to the lens than anything else in the shot – consistent with something on the lens. The blue color may have been just an artifact of the digital camera, but the area around the camera was painted the same electric blue, and so it could have been due to reflected light.

UFOs (shorthand for belief in extraterrestrial visitation – not just unidentified flying objects) have been in the news a bit recently. This is one of those pseudosciences that cycles in popularity, but never goes away. We have been in a down cycle recently, but perhaps we’re seeing a bull market in UFO news, energized by certain recent events. The first came from former astronaut Edgar Mitchell, who claimed in an interview that he was “briefed” by NASA about their alien UFO cover-up.

The UFO community seems more excited, however, about a little-known British hacker named Gary McKinnon, whose hacker name is “Solo.” Recently his appeal to avoid being extradited to the US failed – so he will be coming to America and faces up to 70 years in prison. McKinnon claims that he hacked into many NASA, Pentagon and other military computers, using a dial-up modem, between 2001-2002 because he was trolling for evidence of a US government coverup of ET action – and that he has found it.

Terri Schiavo suffered a heart attack in 1990 at age 26. As a result she had cardiac arrest and although she was revived the resultant lack of blood supply to her brain caused significant damage. For the next 15 years Terri remained in a persistent vegetative state (PVS), requiring a feeding tube for hydration and nutrition but able to breath on her own. PVS results from significant damage to both hemispheres of the brain. The more primitive and basic function in the deep parts of the brain and the brain stem may be intact, but the thinking part of the brain is too damaged to allow for consciousness.

Although there is nothing particularly interesting in the Schiavo case from a neurological perspective – PVS is not uncommon – in 2005 the case came to national attention. The story involved her husband, who wanted to remove her feeding tube and allow her to die, and her parents, who sought legal action to prevent the removal of her feeding tube. The conflict surrounding Terri Schiavo became a test case for the religious right’s support for right to life issues, the right of a husband to make life and death decisions for his comatose wife, the right of her family to intervene, and the role of the government in such decisions. Emotions ran high on all sides as the case touched on the right to life vs the right to privacy issue that remains very divisive in this country. A media storm ensued.

Somewhat lost in all the politics, however, were the medical facts underlying the case. Now a new study (the paper is not available without a subscription, so I linked to the press release) published yesterday online in the journal Neurology reviews the media coverage of the Schiavo case, focusing on the completeness and accuracy of the reporting. Not surprisingly, the study authors found the coverage to be wanting.

I didn’t think that Amanda Peet could get any sexier for standing up for science and the safety of vaccines, but her appearance on Good Morning American yesterday was outstanding. Here is the money quote:

“It seems that the media is often giving celebrities and actors more authority on this issue than they are giving the experts. I know it’s a paradox, but that’s part of why I wanted to become a spokesperson, to say to people, ‘Please don’t listen to me. Don’t listen to actors. Go to the experts.'”

Is it crazy of me to think that maybe Ms. Peet read my blog entry where I made the exact same point? I applauded her efforts while simultaneously pointing out that the media gives far too much attention to celebrities on this issue. Even still, GMA is playing the debate over vaccines as a battle between Amanda Peet and Jenny McCarthy – Um…maybe the scientific medical community might have an opinion as well.

Peet gets it exactly right – she is just being a spokesperson for expert consensus opinion – not substituting her own scientific opinion.

Meanwhile, the new pinup girl for the anti-vaccination movement, Jenny McCarthy, has been trying to get the troops out to counter the new American Academy of Pediatrics effort to promote vaccinations. Orac has the scoop – and he correctly points out such efforts to thwart the AAP’s initiative shows that McCarthy is full-blown anti-vaccine, not “pro-safe vaccine” as she unconvincingly claims.

But I suppose you want a somewhat longer answer. This question comes up frequently among thoughtful skeptics, and also among critics of science. The critics often use a challenge to logic as a way of promoting relativism and the claim that we cannot really know anything. If all pretense to knowledge is ultimately vain and self-deception, they argue, then science holds no special position with regards to truth about the natural world. Therefore any crank notion is just as good as the mainstream scientific consensus.

When this line of reasoning is applied to logic (rather than the empiricism of science) the argument generally takes the form of – how do we know that logic, as currently defined, is correct? Perhaps it is just the way our brains work. A related question is – can the rules of logic be different in a different universe? Did we learn the rules of logic by observing our universe?

My beef with herbal concoctions is not that they cannot work (like homeopathy or therapeutic touch) but that they are not properly regulated. Herbs contain chemicals that can have a pharmacological action in the body, can alter metabolism, have toxicity, and can interact with other drugs. In other words – they are drugs. They are simply not purified and quantified, and most countries do not require testing for herbs similar to pharmaceuticals. So they are unreliable drugs.

But another dirty little secret of the supplement industry is the occasional use of actual known drugs in supplement preparations to give it a real and quantifiable effect. The most common example of this are diet supplements, which commonly contain stimulants. I recently surveyed all the diet supplement products at my local grocery store and almost all of them had some form of caffeine as a major ingredient. It used to be common for such products to contain ephedra (another stimulant) – until it was banned by the FDA for causing cardiac deaths.

Last week Canadian news agencies reported about the death of trucker Michael Berggren, who fell asleep at the wheel. Routine blood screening turned up estazolam – a strong and addictive sedative in the benzodiazempine class of drugs (the same class as valium). Estazolam is not commonly sold in the US or Canada so this presented a bit of a mystery. It turns out that Berggren was likely getting the drug, unknowingly, in an herbal supplement he was taking called Eden Herbal Formulations Serenity II Pills.

Several interesting papers have come out of the recent International Conference on Alzheimer’s Disease, but the one to make headlines was that of Professor Claude Wischik. He has been doing research into tau protein, the protein that forms the neurofibrillary tangles that make up one of the pathological hallmarks of Alzheimer’s disease and is a cause of the death of neurons. He presented data on a new drug, Rember (methylthioninium chloride) that in a phase II trial of several hundred subjects reduced the progression of the disease by 81%.

Alzheimer’s Disease (AD)

AD is a neurodegenerative disease – a category of neurological disorders that involve the death of one or more populations of cells within the nervous system. Their causes are largely unknown, but are likely different among the various degenerative diseases and there is likely multiple mechanisms even within individual syndromes. If the word “disease” is attached to the name of a neudegenerative disorder, that implies that there are specific features (usually pathological) that distinguish it and a specific pathophysiological entity. For example, Parkinsonism is a category of neurological disorders that have the same signs and symptoms. Parkinson’s disease is one such disorder that has specific pathological findings on brain biopsy (although is also has a unique clinical feature – response to dopamine – and so that is how the diagnosis is typically made).

Likewise, AD is a disease (actually it is further divided into two diseases, an inherited form and a sporadic form) – it can only be diagnosed specifically by looking at brain tissue under a microscope. Therefore most people walking around with the diagnosis of Alzheimer’s disease really have a diagnosis of Alzheimer’s type dementia. Dementia is any chronic illness involving global loss of cognitive function, especially memory. Alzheimer’s type means that other causes have been ruled out. That’s it – dementia with a negative workup for a specific treatable cause is Alzheimer’s type dementia, which is often conflated with Alzheimer’s disease, because most of the time they are in fact the same thing. But the diagnosis of AD is usually not confirmed (if at all) until autopsy. Brain biopsies are generally not done because it is an invasive procedure and it will not effect treatment.